58 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



aa. Tertials broadly margined with cinnamomeous or dull rusty. (Young.) 

 h. Kump concolor with back. 



c. Darker Stelgidopteryx ridgwayi. young (p. 61) 



cc. Lighter Stelgidopteryx serripennis, young (p. 58) 



Stelgidopteryx salvini, young (p. 62) 

 hh. Rump pale grayish or dull whitish, conspicuously different from color of back. 



Stelgidopteryx ruficollis uropygialis, young (p. 63) 



STELGIDOPTERYX SERRIPENNIS (Audubon). 



KOUGH-WINGED SWALLOW. 



Adults {sexes aZ^>?•^).— Above, including sides of head and neck, plain 

 grayish brown (deep hair brown), of very nearly uniform tone 

 throughout, but pileum slightly darker than rump, the remiges and 

 rectrices, however, decidedly darker than other parts; « chin, throat, 

 chest, sides, and flanks plain pale grayish hair brown or brownish gray, 

 the chin and throat^ usually somewhat paler than chest and sides; rest 

 of under parts white, including whole of under tail-coverts; under 

 wing-coverts and axillars light grayish brown or brownish gray (inter- 

 mediate in shade betw^een color of back and that of chest), the marginal 

 coverts with paler tips; bill black; iris brown; legs and feet dusky 

 horn color or blackish. 



Young. — Similar to adults, but upper parts more or less washed or 

 overlaid by pale cinnamon or fawn color, the wing-coverts being 

 broadly tipped and the tertials broadly margined (except on inner 

 webs) with the same; chin, throat, and chest (sometimes sides and 

 flanks also) more or less strongly tinged with paler cinnamon or fawn 

 color. » 



Adult ma7d.— Length (skins), 112-133 (123.2); wing, 101-118 (110.7), 

 tail, 4T-55 (50.4); exposed culmen, 5-7 (6.1); width of bill at frontal 

 antia?, 4-6 (5.2); tarsus, 10-12 (11); middle toe, 9-11 (9.9).^ 



Adult female.— Lerxgih. (skins), 108-124 (117); wing, 99-113 (104); 



edly requires subdivision. The bird from Guiana, for example, is like the Colombian 

 form except that the rump is much darker, nearly concolor with the back. 



Hirundo ruficollis Vieillot, Nouv. Diet. d'Hist. Nat., xiv, 1817, 523 (Paraguay). 

 Stelgidopteryx ruficollis Baird, Review Am. Birds, May, 1865, 315, footnote ( Brazil ) . 

 Stelgidojiteryx ruficollis ruficollis Bangs, Proc. New Engl. Zool. Club, ii, July 31, 



1901, 58 (La Plata region, Brazil, and Bolivia; descr. ). 

 Hirundo jugularis Maximilian, Reise Bras., i, 1820, 345 (Brazil; type now in 



coll. Am. Mus. Nat. Hist.).— Temminck, PI. Col., iv, pi. 161, fig. 2. 

 H[irundo'] flavigastra D'Orhigny and Lafresnaye, Mag. de Zool., 1839 (Synopsis 

 Avium, 69) (Corrientes, Argentina). 

 « The under surface of the tail shows a more or less marked, almost abrupt, con- 

 trast between the brownish gray of the basal two-thirds (more or less) and the dusky 

 terminal portion. 



*Some specimens show a tinge of pale cinnamon or buffy on chin and upper throat. 

 This is possibly a remnant of the immature plumage, characterizing birds in their 

 second year. 

 c Thirty-two specimens. 



